Typically, gas turbine engines include a compressor for compressing air, a combustor for mixing the compressed air with fuel and igniting the mixture, and a turbine vane assembly for producing power. Combustors often operate at high temperatures that may exceed 2,500 degrees Fahrenheit. Typical turbine combustor configurations expose turbine vane assemblies to these high temperatures. As a result, turbine vanes must be made of materials capable of withstanding such high temperatures. In addition, turbine vanes often contain cooling systems for prolonging the life of the vanes and reducing the likelihood of failure as a result of excessive temperatures.
Typically, turbine vanes are formed from an elongated portion forming a vane having one end configured to be coupled to a vane carrier at an endwall and an opposite end coupled to another endwall. The vane is ordinarily composed of a leading edge, a trailing edge, a suction side, and a pressure side. The inner aspects of most turbine vanes typically contain an intricate maze of cooling circuits forming a cooling system. The cooling circuits in the vanes receive air from the compressor of the turbine engine and pass the air through multiple flow paths designed to maintain all aspects of the turbine vane at a relatively uniform temperature. The air passing through these cooling circuits in the first stage of a turbine assembly is exhausted through orifices in the leading edge, trialing edge, suction side, and pressure side of the vane. While advances have been made in the cooling systems in turbine vanes, a need still exists for a turbine vane having increased cooling efficiency for dissipating heat.
Often times, a fillet is formed at the intersection of a turbine vane and an endwall to increase strength of the connection and to prevent premature failure of the vane at this locale. While the fillet provides additional strength to the connection, the fillet also adds material, which causes an increase in temperature of the material forming the fillet region relative to other areas forming the outer wall of the airfoil during use of the turbine vane in a turbine engine. Thus, an cooling system is needed that accounts for the difference in material thickness at the fillet region by removing the excess heat to prevent premature failure of the airfoil at the intersection of the airfoil and an endwall.